Synthesis and characterization of 3-phenyl-4[H]-4-[one]-benzopyran (isoflavone) derivatives as potential mesogens

Abstract

With few mesogenic chromone derivatives in the literature the synthesis of 7-[4′-n-alkyloxybenzoyloxy) isoflavones was carried out. The resulting homologous series was characterized by elemental analysis and spectroscopic techniques. The first four members of the series only exhibit a nematic phase. In addition to the nematic phase, the smectic phase commences from the pentyloxy derivative. The decyloxy and higher derivatives only exhibit a smectic phase. The smectic phase observed in the present series is the smectic A type. Differential scanning calorimetry studies served the dual purpose of confirming the microscopic transition temperatures, as well as the calculation of the enthalpies of the various phase transitions.